It’s very easy to create a new to-dos based on email conversations. Most importantly, Things creates a to-do that links back to the Gmail conversation.

How to configure Things app

In Thing app go to Things > Preferences > Quick Entry.

Uncheck the Enable shortcut for Quick Entry with Autofill checkbox and then check it again.

When prompted, download a fresh copy of the Things Helper and run it — it’ll be automatically installed into the right location and the feature will be fully functional again.

How it works

If Mailplane 3 is open, restart it.

In Mailplane 3: open a Gmail conversation.

Select some text inside the conversation, it’ll be added as Things to-do note:

Select Mailplane 3 > Services > New To-Do Containing Selection as Note or press the hotkey. As a result you’ll get the Things Quick Entry dialog:

Make your changes and press Save to add the to-do. After the dialog closes, the to-do can be found in your Things inbox. Just click the email link and your conversation will magically open inside Mailplane 3.